Elon - Musketeers

Skyentist 2017-03-02 23:47:17 UTC #122

There's a huge amount of brand new engineering they have to do. Not as much as a brand new rocket, but still a ton. That's like saying that because the SLS is using space shuttle engines and srbs it's a relatively easy rocket to build and design too. It's much more complicated than that.

Red_Syns 2017-03-03 01:17:36 UTC #123

I understand it's not the same beast as a single-rocket launch, but I'm sure they've already done much if not most of the theoretical portion of the design and computer simulation. They have a functional rocket design that they are reusing, so all that would be left is test launches to confirm they can get the three first stage rockets to function together and separate without causing issues in the second stage.

Ideally, the entire first stage would be recoverable, but in terms of mission success "all" they have to do is get the second stage to the proper position at the proper velocity, and then separate without issues. Anything beyond that is, technically, irrelevant to mission success.

Edit: From what I can tell, the "new" challenges to a Heavy launch are:
-Coordination between the three engines in the first stage (to my utterly untrained knowledge, this could be worked out with ground tests to confirm the three engines can coordinate and react to simulated requirements in changing thrusts)
-Structural integrity of the first stage (again, to my minimally trained knowledge, this is a matter of determining stresses on the rockets and designing the connectors to be sturdy enough to withstand said stresses + whatever safety margin. Obviously it's the unaccounted for that is problematic, but I'm unaware of any multi-rocket stages breaking loose from each other?)
-Booster rocket separation (given that the first stage rockets are all supposed to be landing, the real risk here is the boosters colliding with the centerline rocket. Failure to detach shouldn't pose a problem to mission success in terms of fuel requirements: the fuel that would have been used to land the stage should be adequate to ensure mission success at the cost of not landing the rockets, I would imagine)

I could be wrong, but the emergency escape mechanism has already passed the Falcon 9 requirements at the...I'm sorry, I've forgotten what it's called. The moment when the stresses on the rocket make an emergency escape the most likely to fail. With at least two Falcon Heavy launches planned for this year, I'd be surprised if they have to delay the planned trip by more than a year.

JonnyRedHed 2017-03-03 01:46:10 UTC #124

2018 seems an overly optimistic time frame for a trip around the Moon. More likely 2019>

All the life science systems need to be designed, or finished being designed, then tested to destruction and back again.

I wouldn't want to be the first two guinea pig's on that flight. As exciting as it might be, its also going to be extremely high risk, like good chance of a bad death kind of risky. I'll still be glued to my TV 24/7 watching all the various HD 4k streams and assume there will be a website where you can switch between outside and inside streams and angles. Plus access to some displays and all sorts of data...hopefully.

Red_Syns 2017-03-03 01:56:30 UTC #125

Eh...surviving for a week? Apollo 17 was 12 days, and that was 45 years ago. The ISS has already given us the knowledge for sustaining life (oxygen scrubbing, water reclamation, waste containment) for super-extended periods of time. I understand that the system has to be built and tested, but I don't see that taking terribly long. I'm not sure if SpaceX has any public information on progress of development of the capsule, but again I imagine they wouldn't have offered up a 2018 timeline without having made significant progress in all areas of design and simulation.

As for the bad death risk, most of the causes of death would be either pretty quick or pretty painless. Catastrophic structural failure? Death by fire or death by vacuum, neither taking very long. Oxygen reclamation fails, and not enough left in reserve? Asphyxiation through oxygen deprivation is fairly painless, although a longer process. The mission is not planned to go long enough for starvation, and even a minimal amount of fresh water on hand would last long enough to make dehydration a non-issue even without water reclamation. Honestly, I can't think of too many ways the mission could result in an extended, painful death.

Skyentist 2017-03-03 08:18:40 UTC #126

but I'm sure they've already done much if not most of the theoretical portion of the design and computer simulation.

The same can be said for rocketry and orbital mechanics as a whole. We know when and how to theoretically get to any planet we want. That's the easy part. Space exploration is a engineering problem not a physics problem. Building the hardware is the hardest part.

This is the biggest issue and much more complex than just being sturdy enough. Yes it's just "some computer simulations" but you're basically simulating an entire new rocket and the stresses from the boosters on the first stage is huge. The FH center core has to be reinforced and has a different structural frame because of it. The center core makes it an entirely new rocket. Just because you are reusing the same engine and tanks as your other rocket doesn't meant that that it's an easy fix.

As for a structural failure from a booster challenger comes to mind. It's not exactly the same as breaking loose, but extra complications from new ventures is always dangerous. Their most recent failure (amos6) is a direct example of playing in unknown territory and biting them back.

I am a huge SpaceX fan and I'm confident they will accomplish their goals, but it's important to keep realistic expectations. I expect it to be delayed. FH was originally intended to launch in 2014...another year is likely be cause they've had issues with FH for awhile.

Naiba 2017-03-03 08:37:06 UTC #127

I don't think NASA have had a rocket explode during fueling since before the moonlandings. I wouldn't be trusting Space-X with a moon mission just yet.

How many safe, crewed missions has Space-X pulled off so far, again?

EDIT: And don't forget, they also promised their Red-Dragon mars return mission to be launched that year too, which they promised another re-designed 'Dragon' module for.

Red_Syns 2017-03-03 11:47:56 UTC #128

Last I checked, SpaceX has fixed the fueling issue it had (oxygen was cooled to the point of turning solid). Since it is the same rocket system, multiplied three times, that issue should be corrected as well. Additionally, a crewed capsule would have the emergency escape mechanisms in place that the amos6 did not, so any catastrophic incident should trigger the escape.

I know that you acknowledge it's not the same, but that was a failed o-ring due to operating at an improper temperature. The failed o-ring then released burning fuel that caused a structural failure. I'm not sure what other changes were made during the redesign, but if they are making no changes to the tanks and engines I can't imagine such an issue cropping up.

You are right about the structural redesign of the center tank, of course, I hadn't considered it needing a new frame for the added stresses. That being said, the total maximum thrust of the three engines is a little less than 25,000 kN in a vacuum. Each of the shuttle's SRBs produced 12,000 kN, so even if the centerline rocket does next to none of the lifting until post-separation, we're not looking at new territory in terms of linear forces.

Naiba 2017-03-03 12:35:03 UTC #129

Which should have been caught on the drawing board. Not when they had a finished rocket they were already using.

Red_Syns 2017-03-03 14:00:34 UTC #130

Except they were working with a fuel chilled to the point nobody had ever used before, in a design that had been functioning just fine until that event.

You ask how many crewed missions has SpaceX successfully had, but that is a pointless question. The payload does not determine the success of a launch, the better question is how many failed launches vs. how many successful launches under the current model and revision. To my recollection, there are very few actual mission failures once they started getting successful launches, and the amos6 design flaw has been corrected.

Naiba 2017-03-03 14:09:13 UTC #131

Except the freezing point of oxygen is googleable...

Red_Syns 2017-03-03 14:36:17 UTC #132

Yes, but nobody was expecting liquid helium contamination to solidify the oxygen. I still fail to understand why you think this design flaw would have any impact on the launch schedule of the Falcon 9 Heavy.

Skyentist 2017-03-03 14:57:26 UTC #133

I used it more as an example of not being able to forsee and solve problems that you do not yet know about. I know they fixed it by changing their fueling procedures. No one could have known that using super cooled lox with a faster than normal fueling time would result in an explosion due to weird interactions with a COPV. Now we do. Adding 2 booster cores to a never before flight tested center core design adds a lot of variables whose outcome cannot be predicted. I'm just trying to stress that this is very very difficult so that when it does fly it's even more impressive, and the if/when FH has a failure that it's not entirely unexpected.

Red_Syns 2017-03-03 16:16:21 UTC #134

Sure, I can understand that, and I realize that I am not in the norm when I say that delays are not upsetting. I just don't think it's as improbable for a 2018 mission as everyone seems to believe. We're working with a proven tank/engine design, within the realm of forces we've seen before on multi-rocket designs, on a mission that, in terms of life support, is very minimal. I would love to see all three rockets come back for reuse, but it is not required for the success of a round-the-moon trip and gives a lot of leeway for anything non-catastrophic in terms of "extra" fuel for the launch. The real test will hopefully be this summer, a successful falcon heavy flight will go a long way in demonstrating the tech.

Skyentist 2017-03-03 21:25:10 UTC #135

I've really been wanting to do the math to see if the center core can RTLS and still insert s2 into TLI but I've been too busy since the announcement. I'll definitely look into it when I get home. I have a hunch the boosters will RTLS and the center core will land on OSCILY. The center core will be hauling ass but also there's only been permitting and talk of building a single extra landing pad. If they only have 2 they can't land all 3 at Canaveral.

JonnyRedHed 2017-03-03 23:23:13 UTC #136

We currently know almost nothing about the crew capsule and its life supporting systems. It does seem though that to announce this Elon and his team must be well into the interior design and systems development. But just keeping tight lipped at the moment about revealing anything. Other than the crew capsule shell test flight I've not see much on the capsule.

Q. If two people have paid for the round the moon trip, will there also be SpaceX crew on board. Or will it just be the two paying passengers and everything is done remote. I would of thought at least one or two crew.

Red_Syns 2017-03-03 23:36:24 UTC #137

Eh...you know, I don't know. I'd guess somebody tagging along as a repair person/expert, since there are times when there are no comms.

JonnyRedHed 2017-04-03 03:56:42 UTC #138

Elon Musk’s amazing week

JB47394 2017-04-03 13:09:46 UTC #139

You were in good company in believing that it would be pretty straightforward:

Explaining the delays, the founder of SpaceX said that developing the Falcon Heavy had proven more difficult than anticipated. "At first it sounded easy, but actually no this is crazy hard," Musk said. The company has had to redesign the center core and additional hardware for the upcoming flight, which he deemed to be a fairly high-risk mission.

Edit: Oh, and note that SpaceX is working on a means of recovering the second stage as well. They're gonna have a veritable constellation of parts coming back down.

JonnyRedHed 2017-06-01 10:30:10 UTC #140

Elon to dump Trump over climate bump - theregister.co.uk

Tesla boss says he won't work with The Donald if global warming deal snubbed